The protective member's status of surge protectors can be, as a rule, detected optically directly on the protective member. However, there is very often a requirement for a remote detection of the surge protector's status, or in particular for on a remote information transfer on the surge protector's status which is, as a rule, realized by means of electric signal.
The well-known solutions of a remote signalling of the surge protector state consist of an appropriate arrangement of various mechanical components, by means of which the surge protector state is sensed, or in particular the state of the protective members of particular poles of the surge protector. If there is a status change of at least one protective member, this change is, by means of mechanical components, transferred to a switch, by which status change is formed an electric signal, which is further transferred as an information on the surge protector state through the electric line. By means of such arrangement, it is possible to detect simply and cheaply the status change of the surge protector also at a distance. The definition “switch” is represented by any possible kind of electric components with a switching function, disconnecting function, changeover switch etc., regardless of their magnitude and design. However, for economic reasons there are decreasingly used solutions where each pole of the surge protector is fitted with a switch and there are increasingly used solutions where more poles of the surge protector have one shared switch.
One of such solutions is the one according to DE 38 05 890 C2 in which protective member brackets of particular poles of the surge protector are mutually connected and they are fitted with a shared drawbar situated in the direction of the row of brackets over all of the surge protector's poles. The drawbar movement is controlled by mechanical components which, in each of the poles, comprise a number of arms with a number of springs. The position of arms depends on the protective member state. By means of a change of the protective member, it comes to a position change of the arm in the bracket, which is transferred to a drawbar and evokes its movement towards the switch which is positioned in an individual box mounted in the end of the brackets to the last bracket. Due to the action of the drawbar end on the switch, the switch status changes and generates an electric signal which is by an electric line transferred to a relevant distant place.
The disadvantage of this solution, other than higher costs, consists particularly in increased space demands which represent a disadvantage particularly in surge protectors with a lower number of poles.
The disadvantage of the solution according to DE 38 5 890 C2 is eliminated by means of the solution according to DE 100 01 667 C1 which integrates the switch directly into the surge protector bracket. The bracket is made as an independent assembly for 3 or 4 poles of the surge protector, i.e. for 3 or 4 protective members. There is a hinged lever positioned in the bracket which continuously acts on the switch only if none of the poles is disconnected from the main supply. Each pole is fitted with a mechanical component and a spring which, while disconnecting the surge protector pole from the main supply, causes tilting the arm from its normal position cancelling its action on the switch. Due to this, the switch changes status causing an electric signal which is further transferred by an electric line into the particular remote destination.
The disadvantage of this solution is that it is bound to the particular arrangement of the bracket according to DE 100 01 667 C1. Another disadvantage is that the signalling function does not allow rotation of the varistor insert through 180° which is given by assymetric positioning of the indicating component of the varistor insert. Another disadvantage consists in a permanent action of the hinged lever on the switch, until comes to a disconnection of any of the protective members of the surge protector from the main supply which is demanding on a regular and long-durable pressure setting of the hinged lever onto the switch.
There is also known a solution according to DE utility design Nr. 20 2004 006 227 U1, which also employs a hinged lever mounted in the bracket of the protective member or members. The hinged lever is in the normal state continuously pressed down to the switch and the mechanical components indicating the state of the surge protector protective member do not act against the lever. Provided that then a status change of the protective member occurs, the mechanical components indicating this change begin to act against the action of the spring pressing the hinged lever to the switch by means of another spring (mounted as a part of the mechanical components), by means of which comes to an internal status change of the switch which generates an electric signal, which is being transferred through an electric line to the relevant remote destination.
The disadvantage of this solution consists in that it needs a coordinated action of a number of springs, by means of which this solution is sensitive to manufacturing variations in the system of used elements and also sensible to a contingent time-stability of the parameters of particular springs. It results in usage limitation of one switch for only a small number of surge protector poles, while concurrent demand on relatively heavy duty design of the hinged lever by virtue of acting forces magnitude and possible deformations, which represents another drawback of this solution.
The goal of the invention is to eliminate or at least to minimize the drawbacks of the present background art.